High pressure extraction capsule

ABSTRACT

A high pressure extraction capsule ( 1 ) for single beverage preparation has a porous hydrophobic membrane ( 5, 10 ) that acts as a barrier to fluid flow up to a certain pressure and exceeding said pressure allows for extracting the fluid with active ingredients but still acts as a barrier to particles, particularly ground herbs or roots, wherein the pore size of the membrane ( 5, 10 ) is bigger than 0.45 μm and wherein the hydrophobic membrane ( 5, 10 ) is arranged to have a surface tension of less than 40 dynes/cm. The capsule ( 1 ) comprises an inlet port ( 2 ), a compartment ( 3 ) for holding a substance with active ingredients like, e.g. ground herbs or roots, an outlet port ( 4 ) and a hydrophobic membrane ( 5, 10 ) that separates the compartment ( 3 ) from the outlet port ( 4 ).

FIELD OF THE INVENTION

The present invention relates generally to preparing ready-to-drinkbeverages that have the potential of treating or preventing diseases orenhancing the health of a human. In certain embodiments, the inventiondiscloses a multi-compartment capsule that is capable of extractingactive ingredients using high pressure in one compartment and mix thatextract with the ingredients of the downstream compartment and extractthe downstream ingredients at same or lower pressures in order toprovide a freshly mixed extract for consumer use.

BACKGROUND OF THE INVENTION

Herbs have been used in tea bag formats for decades now with claims toimprove well-being of consumers. Many customers would select herbs overdrugs since they are natural ingredients that usually have no sideeffects. However, the making of a drink from herbs requires tea bags andsome time for preparation of the drink. The herbs in the tea bags areusually dried and preprocessed, which reduces the potential of enhancingthe health of the consumer. Furthermore if the tea bag is stored forsome time before preparing the drink the taste and health enhancingquality of the herbs degrade as well.

During the past few years there has been a significant increase indevices, methods and capsules used to prepare ready-to-drink beverages.Companies like Nestle and Kourig already have household products in themarket that serve consumers hot or cold tea and/or coffee.

Most of the capsules used for ready-to-drink beverages contain a coffeefilter or a coarse nonwoven material to retain the ground particles.Membranes have also been incorporated into capsules for various reasons.

For example in WO 2010112353 A1 that focuses on a capsule with filterfor preparing a liquid nutritional or food composition, usage of a weakmembrane layer is described that will rupture at a given pressure.

In WO 2009092629 A1 a sterilizing grade membrane having a 0.2 μm ratedpore size and made of polyethersulphone, cellulose acetate or polyamideis used to retain the possible bacteria that are present in thebeverage. They also mention that it may be problematic to filter someinfant formulas since they contain probiotics; i.e. good bacteria thathelps digestion.

The document WO 2008117329 A1 describes a capsule with a perfectly flattop, containing a filter paper at the entrance of the capsule in orderto create a homogeneous flow path into the capsule.

However, WO 2010128031 A1 teaches away from such a concept since such alarge filter surface at the entrance of the capsule requires a thick andrigid plastic support underneath and those additional parts increasesthe price of the capsule. Also mentioned is the environmental impact ofthese additional plastic parts. It is claimed that the filter surfaceshould be much less than the mouth of the capsule to minimize theplastic usage as support. Furthermore the idea of cleaning the incomingwater has been introduced in order to increase the quality of the waterby filtering it from microorganisms and viruses.

However, in order to prepare the drink from a capsule a liquid, e.g.water, must be injected into the capsule and then remain in the capsuleas long as required to extract the active ingredients from the groundherbs and roots. Afterwards, the solution comprising the liquid and theactive ingredients must be ejected from the capsule. Usually thisrequires a device that is capable of holding the capsule and providingthe required liquid streams into the capsule and out of the capsuleafter uptake of the active ingredients. In order to ensure properpreparation of the herb containing beverage the amount and pressure ofthe liquid must be within predetermined ranges of parameters.

It is an objective of this invention to provide for a capsule thatallows for easy preparation of beverages with active ingredients fromherbs and roots.

SUMMARY OF THE INVENTION

The present invention addresses, among other things, a novel membranebased capsule design that includes a valve system for ready to drinkbeverages.

For this, the invention relates to a high pressure extraction capsulefor single beverage preparation with a porous hydrophobic membrane thatacts as a barrier to fluid flow up to a certain pressure and exceedingsaid pressure allows for extracting the fluid with active ingredientsbut still acts as a barrier to particles, particularly ground herbs orroots, wherein the pore size of the membrane is bigger than 0.45 μm andwherein the hydrophobic membrane is arranged to have a surface tensionof less than 40 dynes/cm, i.e. less than 40 mN/m.

Water intrusion pressure for a membrane is a function of its surfacetension and it pore size. Increasing amounts of superhydrophobicchemistry and decreasing the pore size will increase the water intrusionpressure. Therefore, by arranging the membrane to have superhydrophobiccharacteristics that equals a surface tension of less than 40 dynes/cmwill provide for a valve effect that facilitates usage of such membranein a capsule.

The benefit of such a membrane is four fold. First, the membraneprovides for filtration of the ground herbs and roots, which is alreadyknown from prior art. Secondly, the membrane provides for retention ofbacteria that can potentially be introduced into the drink via the herbsor roots or by the liquid that is used for fabrication of the beverage.Thirdly, the membrane provides resistance to the liquid flow, i.e. waterflow, and allows for building up a predetermined pressure to facilitatehigh pressure extraction of active ingredients of the ground herbs androots. According to the invention a suitable membrane can be capable ofwithstanding high pressures, e.g. like more than 100 psi, i.e. more thanapprox. 690 kPa or 6.9 bar. By adapting the hydrophobic characteristicsand the pore size the water resistance pressure can be predetermined toa given value in the range between e.g. 15 psi and more than 100 psi,preferably between 50 psi and 75 psi (i.e. between approx. 130 kPa/1.3bar and more than 690 kPa/6.9 bar, preferably between approx. 345kPa/3.5 bar and 517 kPa/5.2 bar). The membrane then acts like a valveand prevents water from crossing the membrane if the pressure is lessthan the predetermined water resistance pressure. The water that hasbeen injected into the capsule will remain within the capsule andextract the active ingredients from the ground herbs and roots,resulting in a solution of active ingredients in water. However, if thepressure that is applied to the water upstream of the membrane isincreased and exceeds the pressure value of the predetermined waterresistance pressure, the membrane becomes permeable for the solution andallows for discharging the solution from the capsule. Fourthly, thehydrophobic membrane enables a user friendly and clean capsule disposalstep upon beverage preparation for the end user, i.e. non-drip capsule.When beverage preparation is complete and the water pressure isreleased, depending on the material and surface tension of the membrane,the membrane becomes hydrophobic again i.e. the membrane valve closes.This property of the membrane enables the upstream accumulated liquid,if any, to be retained in the compartment, preventing a spill during thedisposal of the used capsule.

This novel capsule design eliminates the effects of packing density ofthe ground herbs on extraction pressure build up. Resistance to flow iscreated by the hydrophobic membrane. Therefore, there is no need for adense porous structure created by the compacted microparticles of theground herbs and roots in order to retard the fluid within the capsulefor increased uptake of active ingredients.

High permeability is another important characteristic of the membranesused in a ready to drink beverage. A membrane with high permeabilityonly requires coverage of a small area in a capsule and thereforeresults in low manufacturing cost. There is, however, a trade-offbetween permeability and water intrusion pressure (pore size) for ahydrophobic filtration membrane. Greater intrusion pressures can beachieved by sacrificing permeability. Therefore the preferred way ofincreasing water intrusion pressure is manipulating the surface energyi.e. the surface tension of the membrane.

Preferably the hydrophobic membrane is arranged to have a surfacetension of less than 35 dynes/cm, more preferably approx. 30 dynes/cm.Such a superhydrophobic membrane can have a large pore size but stillact as a valve, i.e. at the same time have a large water resistancepressure. As soon as the water pressure exceeds the predetermined waterresistance pressure, the membrane opens and has a high permeability,resulting in a large flow of solution through the membrane andcorrespondingly short discharge times for emptying the compartment.

For some applications it might be desirable to provide for even morewater resistance pressure. The hydrophobic membrane can be arranged tohave a surface tension of less than 25 dynes/cm or even less than 20dynes/cm.

According to an embodiment of the invention the pore size of thehydrophobic membrane ranges from 0.45 μm to 10 μm, preferably from 0.45μm to 5 μm. Pore sizes below 0.45 μm reduce the permeability and resultin undesired long discharge times. However, pore sizes above 5 μm or 10μm will no longer effectively filter the most common bacteria thatshould not remain in or be added into the beverage.

A particular capsule according to the invention comprises an inlet port,a compartment for holding a substance with active ingredients like, e.g.ground herbs or roots, an outlet port and a hydrophobic membrane thatseparates the compartment from the outlet port. The characteristics ofthe hydrophobic membrane control the required pressure and the retentionperiod of the liquid within the compartment and therefore the maximumuptake duration for transferring the active ingredients of the groundherbs into the solution.

In order to support the hydrophobic membrane a nonwoven backing can beused. Particularly for membranes with a high water resistance pressureit is advantageous to combine the membrane with a supporting nonwoventhat adds to the strength of the membrane.

According to a preferred embodiment of the invention the hydrophobicmembrane is supported by a support means of the capsule. Said supportmeans may comprise a web-like support structure or radially inwardextending protrusions mounted at side walls of the compartment thatextend over the area that is covered by the hydrophobic membrane. Suchsupport means can possess sufficient resisting power to hold themembrane in place and to prevent any damage to the membrane that mightbe incurred by excess pressure or a high liquid throughput.

In order to enable new possibilities for easy preparation of beveragesthat contain different ingredients the capsule comprises a firstcompartment and a second compartment, wherein the inlet port opens intothe first compartment and the second compartment opens out into theoutlet port, wherein a first membrane separates the second compartmentfrom the outlet port, wherein the first compartment is separated fromthe second compartment by means of a second membrane, and wherein,preferably but not necessarily, the second membrane has a higher waterresistance pressure than the first membrane. A first ingredient thatrequires high pressure for extracting the active ingredients intosolution can be placed in the first compartment and a second ingredientwith active ingredients that are best dissolved at lower pressure isplaced in the second compartment. Depending on the location of themembrane having higher water resistance pressure, e.g. first or secondcompartment, the position of the ingredients can also be swapped.

For preparation of the beverage a fluid like, e.g. water, is filled intothe capsule. At low pressure the water cannot penetrate the second highpressure membrane and remains in the first compartment. The waterextracts the active ingredients that are positioned in the firstcompartment until the pressure is raised above the predetermined waterresistance pressure of the second membrane, e.g. 5 bar. After that thesecond membrane becomes permeable and allows for the water with thedissolved or extracted active ingredients from the first compartment toflow through the second membrane into the second compartment.

In the second compartment there are substances with active ingredientsthat efficiently dissolve at a lower pressure, e.g. 0.1 bar. The firstmembrane that is positioned between the second compartment and theoutlet port has a water resistance pressure of e.g. 0.1 bar that is muchlower than the water resistance pressure of the second membrane. Thesolution that permeated from the first compartment only stays for ashort duration of time in the second compartment for uptake of theactive ingredients in this compartment. The solution that now containstwo different active ingredients will then be ejected through the firstmembrane. The first membrane may be hydrophilic, as it is not necessaryfor the first membrane to withstand a high pressure of the solution thatcomes from the first compartment. The pore size of the first membranecan be tailored in order to allow for efficient filtration of thesolution before leaving the capsule.

If the beverage shall comprise more than two different activeingredients, the capsule may consist of three or more compartments thatare separated from each other by means of membranes.

In a further embodiment of the capsule a flow distributing member isarranged between two adjacent compartments. The flow distributing memberenhances turbulences of the water flow through the compartments andsupports dissolution of the active ingredients as well as better mixingof the solution within the compartments.

The flow distributing member can be a membrane. The pore size andstructure of the membrane can be arranged to enhance flow distributingeffects of the membrane.

Additional features and advantages of the invention will be set forth inthe detailed description and claims, which follow. Many modificationsand variations of this invention can be made without departing from itsspirit and scope, as will be apparent to those skilled in the art. It isto be understood that the foregoing general description and thefollowing detailed description, the claims, as well as the appendeddrawings are exemplary and explanatory only, and are intended to providean explanation of various embodiments of the present teachings. Thespecific embodiments described herein are offered by way of example onlyand are not meant to be limiting in any way.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate the presently contemplatedembodiments of the invention and, together with the description, serveto explain the principles of the invention.

FIG. 1 schematically depicts a cross sectional view of capsule with onecompartment, wherein an outlet port is covered by a first poroushydrophobic membrane,

FIG. 2 shows a schematic graph representation of the resulting waterresistance pressure as a function of the amount of additionalcrosslinker used for modification of the membrane surface,

FIG. 3 schematically depicts a cross sectional view of a capsule withtwo compartments separated by a second porous hydrophobic membrane,

FIG. 4 depicts a partial sectional view of the capsule that is shown inFIG. 3,

FIG. 5 depicts a partial sectional view of the capsule from a differentpoint of view,

FIG. 6 depicts an exploded view of the capsule that is shown in FIGS. 3to 5, and

FIG. 7 depicts the capsule with a closing lid.

DESCRIPTION OF THE EMBODIMENTS

All publications, patents and patent applications cited herein, whethersupra or infra, are hereby incorporated by reference in their entiretyto the same extent as if each individual publication, patent or patentapplication was specifically and individually indicated to beincorporated by reference.

Before describing the present invention in further detail, a number ofterms will be defined. Use of these terms does not limit the scope ofthe invention but only serve to facilitate the description of theinvention.

As used herein, the singular forms “a”, “an”, and “the” include pluralreferents unless the context clearly dictates otherwise.

For the purposes of this specification and appended claims, all numericvalues expressing quantities of ingredients, percentages or proportionsof materials, reaction conditions, and other numerical values used inthe specification and claims, are to be understood as being modified inall instances by the term “about”, whether or not the term “about” isexpressly indicated.

Accordingly, unless indicated to the contrary, the numerical parametersset forth in the description and in the following specification andattached claims are approximations. Notwithstanding that the numericalranges and parameters setting forth the broad scope of the invention areapproximations, the numerical values set forth in the specific examplesare reported as precisely as possible. Moreover, all ranges disclosedherein are to be understood to encompass all subranges subsumed therein.For example, a range of “1 to 10” includes any and all subranges between(and including) the minimum value of 1 and the maximum value of 10, thatis, any and all subranges having a minimum value of equal to or greaterthan 1 and a maximum value of equal to or less than 10, e.g., 5.5 to 10.

The terms “optional” or “optionally” mean that the subsequentlydescribed event or circumstance may or may not occur, and that thedescription includes instances where the event occurs and instanceswhere it does not.

The terms “filter medium”, “filter media”, “filtration media”, or“filtration medium” refer to a material, or collection of material,through which a fluid carrying active ingredients for a ready to drinkbeverage and/or a microorganism contaminant passes, whereinmicroorganism is deposited in or on the material or collection ofmaterial.

The terms “flux” and “flow rate” are used interchangeably to refer tothe rate at which a volume of fluid passes through a filtration mediumof a given area.

The term “capsule” refers to any container that is capable of holdingsolids that can be exposed to a fluid flow. Usually a capsule comprisesa compartment with an inlet port and an outlet port. According to thepresent invention a membrane is arranged to act as a barrier between asection within the compartment that holds the substances with activeingredients and the outlet port.

The membranes are prepared from a broad range of polymers and polymercompounds, including thermoplastic and thermosetting polymers. Suitablepolymers include, but are not limited to, nylon, polyimide, aliphaticpolyamide, aromatic polyamide, polysulfone, cellulose, celluloseacetate, polyether sulfone, polyurethane, poly(urea urethane),polybenzimidazole (PBI), polyetherimide, polyacrylonitrile (PAN),poly(ethylene terephthalate), polypropylene, polyaniline, poly(ethyleneoxide), poly(ethylene naphthalate), poly(butylene terephthalate),styrene butadiene rubber, polystyrene, poly(vinyl chloride), poly(vinylalcohol), poly(vinylidene fluoride), poly(vinyl butylene),polymethylmethacrylate (PMMA), copolymers, derivative compounds andblends and/or combinations thereof.

Non-limiting examples of single or multilayered porous substrates orsupport means include porous film membranes. Porous film membranes areproduced from a variety of thermoplastic polymers, including polyamides,polysulfones, polyvinylidene fluoride, polytetrafluoroethylene,cellulose, cellulose esters, polyacrylonitrile, etc. Methods ofproducing porous film membranes include solution phase inversion,temperature-induced phase separation (TIPS), vapor-induced phaseseparation (VIPS), solvent and chemical etching, room temperature andheat-assisted biaxial stretching, and combinations thereof.

FIG. 1 schematically depicts one embodiment of the present inventionwherein a capsule 1 comprises an inlet port 2 into a compartment 3within the capsule and an outlet port 4. A high pressure membrane 5 isattached to a bottom 6 of the compartment 3 and covers the outlet port4, thereby separating the compartment 3 from the outlet port 4. Withinthe compartment 3 there are ingredients 7 like, e.g. ground herbs androots.

A fluid, e.g. water, can be injected through the inlet port 2 into thecompartment 3. If the fluid is injected with a pressure that is below apredetermined fluid or water resistance pressure of the membrane 5, thefluid cannot exit the compartment 3 and remains within the compartment3. During this time, the fluid dissolves the solvable active ingredientsof the ingredients 7 like e.g. ground herbs and roots and becomes asolution that contains the already solved active ingredients.

If the pressure is increased above the predetermined water resistancepressure of the membrane 5, the membrane 5 becomes permeable and thesolution is ejected from the compartment 3 through the membrane 5 andthe outlet port 4.

FIG. 2 shows the resulting water resistance pressure of apolyethersulfone membrane 5 after surface modification with a 4%hydrophobic Zonyl monomer as a function of the amount of crosslinkerused, e.g. hexanedioldiacrylate.

FIG. 2 displays that by surface modification the water intrusionpressure of a cast polyethersulfone (PES) membrane can be easily variedfrom 15 psi to 75 psi, without changing its pore size rating.

The resulting water resistance pressure was determined according to thepressure gauge reading in an apparatus were water is delivered from apressurized tank into a 47 mm stainless steel membrane holder.Pressurized water is applied upstream of the membrane and downstreamside is monitored for any water flow. The pressure at which water startsto flow downstream of the membrane is recorded as the water intrusionpressure.

Flux is the rate at which fluid passes through the sample of a givenarea and was measured by passing deionized water through filter mediumsamples having a diameter of 47 mm (9.6 cm² filtration area). The waterwas forced through the samples using about 25 in Hg vacuum on thefiltrate end via a side arm flask.

Bubble point test provides a convenient way to measure effective poresize. Bubble point is calculated from the following equation:

${P = {\frac{2\gamma}{r}\cos \; \theta}},$

where P is the bubble point pressure, γ is the surface tension of theprobe fluid, r is the pore radius, and θ is the liquid-solid contactangle.

Membrane manufacturers usually assign nominal pore size ratings tocommercial membrane filters, which are based on their retentioncharacteristics.

Surface tension is used interchangeably with critical wetting surfacetension (CWST) of a porous membrane. CWST is equal to the surfacetension of the highest surface tension solution which wet the porousmembrane in 2 seconds or less. The test is conducted as follows: Onedrop from an eye drop type bottle is added to the porous membranesurface and the time to wet, or penetrate the porous surface, ismeasured. The surface is arbitrary deemed to be wet by the test solutionif the penetration of the surface is 2 seconds or less. CWST testsolutions are prepared by mixing water and isopropylalcohol in variousratios to achieve surface tensions of 21-72 dynes/cm, and by mixingwater and sodium chloride in various ratios to achieve surface tensionsof 73-100 dynes/cm.

In FIGS. 3 to 7 there is shown a capsule 1 with a first compartment 3, asecond compartment 8 and a third compartment 16, wherein the inlet port2 opens into the first compartment 3, the second compartment 8 isbetween the first compartment 3 and the third compartment 16, and thethird compartment 16 opens out into the outlet port 4. A first membrane9 separates the second compartment 8 from the third compartment 16 andthe outlet port 4. The first compartment 3 is separated from the secondcompartment 8 by means of a second membrane 10. Both compartments 3 and8 contain ingredients 7 with solvable active ingredients that will besolved by the fluid that streams through the compartments 3 and 8. Forsome applications it might be advantageous to insert additionalingredients 7 also into the third compartment 16.

The second membrane 10 has a higher water resistance pressure than thefirst membrane 9. According to the embodiment shown in FIGS. 3 and 4,the second membrane 10 has a water resistance pressure of 5 bar, whereasthe first membrane 9 has a water resistance pressure of 0.1 bar.Therefore, the first compartment 3 contains ingredients 7 with activeingredients that require long exposure time or high fluid pressure foreffective dissolution. In the second compartment 8 there are ingredients7 with active ingredients that easily dissolve at low pressure or shortexposure times. By way of example, the first compartment 3 may containground herbs and roots with active ingredients that are difficult todissolve, and the second compartment 8 may contain other ground herbs orroots that are easily dissolved. According to another example the firstcompartment 3 may contain ground coffee, whereas the second compartment8 contains milk powder. According to yet another example the firstcompartment 3, the second compartment 8 and the third compartment 16 maycontain three different ingredients for a dietary supplement drink.

The second membrane 10 is supported by a support disc 11 with manyopenings 12 that result in a web-like configuration of the support disc11. As shown in FIG. 4, the first membrane 9 may be supported byradially inward extending protrusions 13 that are arranged in order toprovide for a flat mounting support for the membrane 9.

It is also possible to support the first membrane 9 by a support disc11′ that is similar to the support disc 11 for the second membrane 10.The capsule 1 with support discs 11 and 11′ are shown in FIGS. 5 to 7.

For manufacturing the capsule 1 a housing 14 as well as the firstmembrane 9 and the second membrane 10 are prefabricated. The waterresistance pressure of the first membrane 9 differs from the waterresistance pressure of the second membrane 10 in a manner that the waterresistance pressure of the second membrane 10 is significantly higherthan the water resistance pressure of the first membrane 9.

The first membrane 9 is introduced into the housing 14 and mounted abovethe radially projecting protrusions 13. Afterwards, the alsoprefabricated support disc 11 is mounted in the housing 14 of thecapsule 1 at a distance to the first membrane 9. The second membrane 10is mounted on top of the support disc 11. The second membrane 10 is at adistance to the first membrane 9 as well as at a distance to the inletport 3 of the capsule 1. The first membrane 9 then separates the housing14 of the capsule 1 into the third compartment 16 and the remainingfirst and second compartment 3 and 8, whereas the second membrane 10separates the housing 14 of the capsule 1 into the first compartment 3and the second compartment 8. Of course instead of the radiallyprojecting protrusions 13 an additional support disc can be placed abovethe outlet port 4, if the first membrane 9 requires such a support.

The capsule 1 can be sealed with a closing lid 15 that is only shown inFIG. 7. The closing lid 15 may be either rigid or flexible and can bemade of any suitable material.

The disclosure set forth above may encompass multiple distinctinventions with independent utility. Although each of these inventionshas been disclosed in its preferred form(s), the specific embodimentsthereof as disclosed and illustrated herein are not to be considered ina limiting sense, because numerous variations are possible. The subjectmatter of the inventions includes all novel and nonobvious combinationsand subcombinations of the various elements, features, functions, and/orproperties disclosed herein. The following claims particularly point outcertain combinations and subcombinations regarded as novel andnonobvious. Inventions embodied in other combinations andsubcombinations of features, functions, elements, and/or properties maybe claimed in applications claiming priority from this or a relatedapplication. Such claims, whether directed to a different invention orto the same invention, and whether broader, narrower, equal, ordifferent in scope to the original claims, also are regarded as includedwithin the subject matter of the inventions of the present disclosure.

1. High pressure extraction capsule (1) for single beverage preparationwith a porous hydrophobic membrane (5, 10) that acts as a barrier tofluid flow up to a certain pressure and exceeding said pressure allowsfor extracting the fluid with active ingredients but still acts as abarrier to particles, particularly ground herbs or roots, wherein thepore size of the membrane (5, 10) is bigger than 0.45 μm and wherein thehydrophobic membrane (5, 10) is arranged to have a surface tension ofless than 40 dynes/cm.
 2. High pressure extraction capsule (1) accordingto claim 1, whereby the hydrophobic membrane (5, 10) is arranged to havea surface tension of less than 35 dynes/cm, preferably approx. 30dynes/cm.
 3. High pressure extraction capsule (1) according to claim 1,whereby the hydrophobic membrane (5, 10) is arranged to have a surfacetension of less than 25 dynes/cm, preferably approx. 20 dynes/cm. 4.High pressure extraction capsule (1) according to claim 1, whereby thepore size of the hydrophobic membrane (5, 10) ranges from 0.45 μm to 10μm, preferably from 0.45 μm to 5 μm.
 5. High pressure extraction capsule(1) according to claim 1, whereby the capsule (1) comprises an inletport (2), a compartment (3) for holding a substance with activeingredients like, e.g. ground herbs or roots, an outlet port (4) and ahydrophobic membrane (5) that separates the compartment (3) from theoutlet port (4).
 6. High pressure extraction capsule (1) according toclaim 1, whereby the hydrophobic membrane (5, 10) is supported by anonwoven.
 7. High pressure extraction capsule (1) according to claim 1,whereby the hydrophobic membrane (5, 10) is supported by a support meansof the capsule (1).
 8. High pressure extraction capsule (1) according toclaim 1, whereby the capsule (1) comprises a first compartment (3) and asecond compartment (8), wherein the inlet port (2) opens into the firstcompartment (3) and the second compartment (8) opens out into the outletport (4), wherein a first membrane (9) separates the second compartment(8) from the outlet port (4), wherein the first compartment (3) isseparated from the second compartment (8) by means of a second membrane(10).
 9. High pressure extraction capsule (1) according to claim 1,whereby the second membrane (10) has a higher water resistance pressurethan the first membrane (9).
 10. High pressure extraction capsule (1)according to claim 1, whereby the first membrane (9) has a higher waterresistance pressure than the second membrane (10).
 11. High pressureextraction capsule (1) according to claim 1, whereby the capsule (1)comprises three or more compartments (3, 8, 16) that are separated fromeach other by means of membranes (10, 9).
 12. High pressure extractioncapsule (1) according to claim 8, whereby a flow distributing member isarranged between two adjacent compartments (3, 8).
 13. High pressureextraction capsule (1) according to claim 12, whereby the flowdistributing member is a membrane (10).